Further details have emerged on the underground explosion that killed shotfirers Patrick McMullen and Holly Clarke at Polymetals Resources’ Endeavor mine at Cobar in New South Wales this week.

The NSW Resources Regulator has indicated that workers were preparing a ballistic disc explosive device to clear a blockage in the draw point of a stope when the tragedy occurred on October 28.

A safety alert stemming from initial investigation said that an unintended initiation of the charge resulted in the fatal injuries to Mr McMullen and Ms Clarke, along with injuries to another woman.

‘The investigation is at an early stage and no definitive causal factors contributing to this incident have yet been identified,’ it stated.

The fatal explosion is understood to have happened about 700m underground around 3am (AEDT) on Tuesday.

Polymetals issued a statement today expressing deepest condolences to the families of Mr McMullen (known as Ambrose) and Ms Clarke.

The third worker involved, MacKenzie Stirling, was currently recovering at home, the company said.

The company identified Mr McMullen, 59, as a mining supervisor and shotfirer while Ms Clarke, 24, was a miner and shotfirer.

“Words fall short of how deeply affected the Polymetals’ family is by this tragic incident,” Polymetals executive chairman Dave Sproule said.

“The feeling of profound sadness when life is lost is never forgotten.  We’re devastated by what has happened and share our deepest thoughts and condolences with the families, their friends and our colleagues.  We are doing everything we can to support those affected.

“The safety and well-being of our team is the company’s highest operational priority.  We are working with the authorities to assist their investigations as to how this incident occurred and will not rest until we understand what happened.”

The company is planning to recommence operations in a staged manner, with personnel returning to work from Wednesday.

Exploration drilling and concentrate transport is expected to recommence next week, as well as completion of planned statutory electrical works. 

Polymetals said counselling would continue for team members with the progressive resumption of mining and processing activities.